Question

. Your lab partner placed 13.6571 g of Na2CO3 into a flask and then added enough water to reach 500.0 mL. What concentration of Na2CO3 solution did your lab partner prepare?

Answer 1

If you want to express your concentration in molarity (M, or mol/L), we will need to find moles of Na2CO3 and litres of solution.

You can find moles of Na2CO3 easily by dividing the mass provided by the molar mass of Na2CO3 (106 g/mol). You also have the volume of solution in the question: 500 mL, which is 0.5 L. Then it's just a matter of dividing moles by volume and you'll have your concentration!

Answer 2

@matt101 I don't come up with the right answer doing that. The right answer is 0.2577 M
Here's what I did: 13.6571/106=.1289
.1289/.05=2.578

Answer 3

You got the right answer, it's just rounded to 3 decimal points (0.258) instead of 4 (0.2577).

Answer 4

My 2 is in front of the decimal

Answer 5

@matt101

Answer 6

Oh that's because you divided by 0.05 instead of 0.5. Remember 500 mL = 0.5 L

Answer 7

Okay. Let me try again

Answer 8

Got it. Thanks!